Comparative study of DTS and CT in the skeletal trauma imaging diagnosis evaluation and radiation dose

To compare the differences between CT (Computed tomography) and DTS (digital tomosynthesis) in the X-ray radiation dose, and to analyze the sensitivity and specificity of each examination to check the suspected fractures and dislocations cases.

From May 2010 to February 2012, 46 patients suspected with fractures and/or dislocations were prospectively enrolled to do the CT and DTS examination on the basis of the results of DR examination. Patients were considered ineligible if they were pregnant or lactating (female subjects only). The Yangzhou Regional Ethical Review Board in Jiangsu province, China approved this study. All 46 patients signed the informed consent. To contrast radiation dose between CT and DTS group of the patients and make statistical analysis. Two experienced experts assess the image quality by I-III grade and make statistical analysis. Draw the ROC of reader A and B according to the golden standard of clinical diagnosis.

The average effective dose of CT Group is 5.46 msv, while average effective dose of DTS group is 0.07 msv.There is significant statistical difference (t=22.89, p<0.01) between them. Calculate and compare the area under the ROC curve of reader A and B. The area of reader A by CT and DTS is 0.999 ± 0.005, 0.973 ± 0.022. The area of reader B is 0.961 ± 0.026, 0.944 ± 0.032. Both of them perform z test, and P>0.05. There is no significant difference. Assess the uniformity of two readers with Kappa test. The Kappa value of reader A and B is respectively 0.757 and 0.783. When the value is greater than 0.75, two readers' uniformity is considered well. The two readers' sensitivity and specificity in diagnosing hidden skeletal trauma with CT and DTS are respectively 97.06% (reader A), 96.97% (reader B); 91.67% (reader A), 84.62% (reader B). Use the χ(2) test to them, then get the same result: P>0.05. There is no statistical significant.

Radiation dose of VolumnRAD DTS only account for 1.5% of CT, but its image can meet the requirements for clinical diagnosis. When fracture and/or dislocation is suspected with DR, VolumnRAD DTS can be recommended firstly as further checks.